Remote-controlled automatic telephone for loud traffic



May 17, 1949. v TSCHUM] 2,470,590

HEMOTE-CONTROLLED AUTOMATIC TELEPHONE FOR LOUD TRAFFIC Filed May 12, 1944 Patented May 17, 1949 REMOTE-CONIDRQIJLED AUTOMA IC IE E- PHONE FOB, LOUD TRAFFIC Otto Tschumi, Soleure, Switzerland, assignor to Autophon Aktiengesellschaft,-Soleure, Switzerland, a joint-stock-company of -Switzerland Application May-12, 1944, Serial No. 535,299 InSwitzerland December 21, 1942 4- Claims.-

This invention relates-to-remote-controlledgautomatic announcing telephone installations.

Heretofore, iftheloud-speaker in a remotecontrolled automatic announcing telephone installation was used-both-for transmitting ordinary calls and'for special signals which are not initiated by operating theconnecting means of the manual exchange, special additional means werenecessary for changing over the telephone from the special useconditions to normal operating conditions. Besides this, in known'installations it was not possibleduring-the special use to determine whether the subscriberin question was called in the-normal manner or; not.

The remote-controlled automatic telephone according to the invention is characterized-in that during use for special purposes, the calling conditions'for normal traffic remainyestablished.

The installation according to the invention comprises a-telephone station with an amplifier and a transducer, Whichlatter is applicable as a loudspeaker and a microphone, whereby the amplifier and the transducenmay" be used not only for receiving and transmitting ordinary telephonic conversations, but also 'for' receiving and transmitting other signals. When reference is made to normal use, normal operating .conditions or normal operation, thismeans usefior receiving or transmitting telephonic conversations, or telephone connection, or ingeneral'. the use of the telephonestation for thereception and transmission of telephonic conversations.

As this reception and transmission of telephonic conversations is the main object of the telephone installations according to the invention, it is referred to generally'in'the. specification as normal (i. e. the usual way of using this installation). In contrast thereto is the special use, (i. e., other oradditional use) of'the telephone station or the amplifier andthe loudspeaker of, said station, thatois', the use for the reception and possibly alsoforthe transmission of other signals, such as',;for"instance, highj-frequency, voice modulated signalsor for thereception of wire broadcasting signals, or'forthe transmission of phonograph records, or, finally;

for theconnection to another telephone'line in addition to anddifiering from the ,ordinaryexchange line. The use oi the telephone stati'o'njior the receptionof such .signals which are not incoming on the ordinary,,,exchan'geline; hasfibeen' called special. use" (i. e., another, additional use) ,I

the rendering audible .of'fthe. signals received; in

this way special reproductions, the, correspond ing reception special'receiving, and the object 2 of usingthe telephone station for these purposes and, in addition thereto, possibly also for connection toanother, separate line or a dictaphone special purpose. "The special operating conditions are accordingly the switch-positions, and

operating conditions which correspond to this special use.

Thus the main purpose or objectof the apparatus in accordance with the invention is the exchange of telephonicconversations on an. exchange'line. Another, addltionalpurpose of the telephone installation is thereception' and pos sibly thetransmission as well as the amplification of signals whichare independent from said ordinary telephonic conversations.

If desired, the arrangement may-be chosen so that, on acall, the normal position of the stations is, atj'leastduringthe normal use, automatically established, so that additional switch devices for the interruption of1the, special useand the establishment of'the normal operating conditionsare nolQnger necessary. Furthermore, measures may be taken allowing an outgoing connection to be made andla'conversation to be had-without the'spe'cial use circuit being manually disconnected. This disconnection takes place automatically uponthe establishment of connections with theautomatic main station.

The accompanying drawings illustrate, by way of example, one embodimentof'theinvention and di-fierent-applicationsof' the same;

Fig. 1 is a diagram-ofthis embodiment;

Fig. 2 shows the application' ofthe circuit to utilization for thereception"and-possibly also-for the transmission of' other signal's such, for'instance, as high frequencyvoice modulated signals;

Fig. '3 shows the utilization of the circuit for the reception of wire broadcasting signals;

'Fig. 4 shows the circuit utilized for thetransmission of phonograph records and the, like; and

Fig.5 showsthe connection .of thesubscriberfs station to another', telephone"line in addition. to the ordinary exchange line. v

In Fig. 1,.3EW designates ,a transducer. capable of operatingeitherasa transmitter ora receiver. According to they manner of ,operation this. transducer is, connected with; either the input; transformer 'EV or theoutputtransforiner [AV of. the amplifier V. The JcOrresp nding change-over switches are, designate bythe'ch ra e M1, an uz. The two contacts,uigandmz, actuatedloy a doubleiwound rel y .Uath i'w hdines .of w ich aredesignated by U82. (high'oh mic) and Uw (low ohmic), are operable so' as to be reversed 3 from the position shown in a full line to that shown in a broken line, when either of said windings is traversed by current. The amplifier V is turned on by closing a contact ei/ua to connect the amplifier with a power source P. The contact ei/us is closed when either one of the windings Us) or Um is energized and is also closed by the energizing of a relay winding E. The winding E also controls contacts (52 and ex. When the winding E is energized the contacts cc and es are reversed from the positions shown in full lines to those shown in broken lines respectively. With the aid of the contact as the incoming side of the amplifier can be brought into connection with a terminal I and transformer Ue or with a terminal 2. The terminals a, b of the transformer Ue are connected with each other by an impedance coil Dr, the middle of which is connected with the impulse contact i of a conventional calling dial NS either over the condenser CI or the contact ES and the contact e2. The impulse contact 2' is grounded over a rectifier arrangement. The contact ea in its rest position connects the impulse contact i over the high ohmic relay US) with the terminal 3, while the terminal 4 is in direct connection with the middle of the impedance coil Dr. The rectifier arrangement comprises essentially a full wave rectifier bridge consistin of four rectifier elements Gh-4, with connection points and 6 and bridging points I and 8. The relay winding E, the contacts of which are designated by cm, is connected across the points i and 8 and is operable by line current in either direction. The connecting point 5 is connected to a lamella of the impulse contact 2' of the calling dial NS whereas the counterpoint 6 is grounded. The one (B) of the two bridging points 1 and 8 is grounded over the low ohmic winding Uw of the double Wound relay U and over a switch sh, whereas the other (1') is grounded on the one hand over a resistance W3 and said contact (sh), and On the other hand connected in parallel over a pilot lamp KL connected in parallel with W3. The low resistance relay winding Um constitutes an element dependent on the kind and direction of current.

It may be mentioned that RW is a regulating resistance, KH an earphone, W1 a first and W2 a second ohmic resistance and, finally, sKH a switch for adjusting the earphone.

The terminals a-b, 1-4 and ER are the outgoing terminals of the installation according to the invention. The terminals a, b are connected, for a given purpose, directly or indirectly to the exchange line designated A, B (Figs. 2-5), whereas the terminals l-4 and ER are connected, according to the purpose, to the corresponding terminals of auxiliary apparatus for the special or additional purposes defined above. In addition to these terminals, there is an external connection to a power source P for the heater current of the amplifier V.

The calling dial NS is an ordinary calling dial as used in automatic telephony. With the calling dial in rest position, the short-circuit contact k is open and the impulse contact 2' is closed, whereas during the winding up of the calling dial and its return, the short-circuited contact k is closed. The impulse contact i remains closed during the winding up of the dial, and during the returning of the dial opens as many times as corresponds to the number selected. With regard to the object of the invention, the calling dial is essential only in so far as, with the beginning of the selecting process, that is, on starting the winding up of the dial and the corresponding closing 01' the short circuit contact 10, the potential existing on the two exchange lines A, B, is applied to the closed impulse contact i to the input point 5 of the rectifier arrangement and the relay winding U9 is thereby bypassed.

The manner of operation of the device shown is as follows:

If the device is to be connected for receiving in a special use, the terminals 3 and l are shortcircuited by the subscriber. The high ohmic relay U9 is thereby inserted into the circuit, resulting in the operation of the switches in, uz and us. Owing to the low amperage caused by the high resistance, the current flowing in the relay E is too small to bring the latter into action. The contacts e1, ez and ex thus remain in their rest position. Consequently, 62 remains in the position shown in solid lines, and results in continued operation of relay U0, while contact 63 switches the audio-frequency signals of the special signals arriving through the terminal 2 to the amplifier. On the other hand, by reversing the contacts in and uz the subscriber device is brought into receiving condition so that the audio-frequency signals arriving through the terminal 2 can be heard in the transducer EW. This, however, is possible only since the amplifier is energized owing to the operation of switch us and in spite of the fact that contact e1 remains in inoperative rest position. In this way, the device is adjusted for receiving the special signals. The calling conditions of the station are assured in that a signal coming in through the terminals a, 1) goes over the condenser CI to the rectifier arrangement and thereby also to relay E. Owing to this additional current relay E actuates its contacts disconnecting both the incoming signals of the special use and the high ohmic resistance of relay U52. By disconnecting this high ohmic resistance at the contact 22 the current in relay E is further increased, so that, even after the calling signals have ceased, the station is in its normal operating condition.

If the normal operation ceases, and the subscriber wishes to be able to take up the special use at once, he takes care that the contacts 3 and 4 remain short-circuited even during the normal operation, which results in the fact that, after termination of this normal operation and the resulting reduction of the direct current in the relay E, the contacts of the latter return to rest position. The high ohmic resistance of relay U9 is again inserted into the circuit by contact 62 (the amplifier being adjusted to hearing condition) and contact 63 leads the signals of the special service again to the amplifier. If, after the normal operation has ceased, the subscriber no longer wishes to maintain the special operating conditions, he separates the terminals 3 and 4 whereby the contacts 61-3 return to their rest position, the amplifier V, however, remains disconnected owing to the non-operation of relay U.

If, during a special use, the subscriber is desirous of carrying out a normal operation, the special use need not be interrupted, but the necessary connection can be established as if there were no special use actually at work. By the operation of the calling dial and the resulting short-circuiting of the sparking contact is, the potential of the terminals a, b is directly connected to the rectifier arrangement, while the high ohmic resistance in relay U9 is bridged over. In this way, the amperage E is increased to such a degree that this relay E comes into action and establishes normal operating conditions.

Figs. 2-5 show the installation according to Fig.1 in its connection to auxiliary apparatus adapted for various other (special) purposes, whereby, for the sake of simplicity, said installation according to Fig. 1 is shown in Figs. 25 in broken lines only as a square which is designated and only the outgoing terminals are desigmated more precisely. In Fig. 2, for instance, it to be seen that the terminals 2-4. as well as a, b and ERare connected to terminals 21, 3|, 4|, 111,121 and ERi of the auxiliary apparatus HG corresponding to the special (or additional) purpose in question. As the terminal I is not used for this particular purpose, it is represented as an unconnected terminal. This auxiliary apparatus consists essentially of a schematically represented high frequency amplifier I-IV and a transformer UeV as wellas of a key T for shortcircuiting the terminals 3 and 4 to establish receiving conditions.

As indicated above, the special (or additional) purpose in the case of Fig. 2 consists in the re- ;production of audio frequency modulated high frequency signals which, just as the ordinary call, are received over the line A, B and which have nothing to do with the normal purpose which consists in receiving and transmitting voice signals during a conversation. As has already been pointed out, the object of the invention consists in adjusting an-installation, as shown in Fig. 1, alternatively for the ordinary transmission of voice signals and also for receiving other signals. These other signals are, in the embodiment of Fig. 2, high frequency signals which likewise are conveyed to the subscriber on exchange line A, B, whereby the adjustment of the condensers C and the inductance coils D causes the high frequency signals to bedirected over the condensers C permitting the passage of high frequency cur- .rents to the auxiliary apparatus I-IG or its high frequency amplifier I-IV, and the low frequency voice current to be directed over the coils D direct to the receiving station EE.

The ground terminal ER is connected to a like terminal ERI of the auxiliary apparatus HG and is grounded.

By Z it is indicated in Figs. 2-5 that the line A and B is the exchange line coming from the central station Z.

In accordance with the special use of Fig. 2 "an audio frequency modulated high frequency signal is received over the terminals a, b and over the transformer UeV of high-frequency amplifier HV, after the called subscriber has established receiving conditions by operating the key T.

If, during the special use, the receiving station is now called by the main station, the call, owing to the device according to the invention, is perceived and the connection at once established.

In Fig. 3, besides the schematically shown receiving station EE, an auxiliary apparatus TZ is shown which permits, as a further, additional purpose, receiving wire broadcasting signals in addition to the ordinary voice signals of the telephone trafllc. In this embodiment, the terminals I and 2 are not used and may, therefore, be short-circuited. The terminals 3 and 4 of the receiving station EE are to be connected to the corresponding terminals 32, 42 of the auxiliary apparatus T2 and can be short-circui ted by the key T. The aim of this short-circuiting has already been described in connection with Figs. 1 and 2. The terminals a, b are connected to the corresponding terminals as and ha of the auxiliary apparatus, which terminals (12 and D2 of said apparatus are brought partly (a2) direct and partly (In) over a :selecting-key W'I to. the output tere minals as andxba to'which theexchange line A, Bis connected. Here, again, .ER. .is the ground terminal which; is.-connected to y a; like terminal (ERz) of the auxiliary apparatus TZ, whereby the selecting key WT may be grounded tempo- .rarily by known means (not shown) in order to change the program, which change is made at the central station Z.

The condition forsbroadcast receiving is established by closing the key T while with the selecting key WT a. program-selecting switch can be changed over by the disconnection and direct grounding of the wire B. Here, too, a call coming from the main station Z is received automatically and the connection with :the main station Z established. At the same time the telephone broadcasting is disconnected from the receiver.

In Fig. 4, the additional or special purpose consists in the reproduction of phonograph records or magnetic: recordings. The auxiliary apparatus is designated by WE and consists substantially only of a-switch S1 and the connecting terminals 23, 33, 43, 9 and I0. One of the poles of the pick-up of a phonograph or the sound head of a magnetic recorder (not shown) is connected to the corresponding terminals 3 and 4 of the installation EE. To the terminals 9 and It is connected the driving motor of a phonograph or the steel tape of a magnetic recorder (not shown). Of the other terminals of the installation, terminalER isgrounded, whereas to the terminals a and-b is-con-nected the exchange line A, B, coming from the central station Z.

Terminal l is not-used. It follows from the-arrangement shown in the drawing, when switch Sr is reversed, not only the circuit of a driving motor (not shown) is closed, but also the terminals 33 and or 3 and =4-are short-circuited.

The effect thereof is that the installation EE is adjusted to this :special (additional) reproduction and the signals coming in over the terminals 23 and v2 become audible in the electro-acoustic transformer EW,-as shown in Fig. 1.

In Fig. 5, the special purpose consists in the reception of a direct second telephone communication which isindependent from the normal.' or main ordinary line.

The normal (or main) communication is led-in from the central station over the terminal a, b, whereas the additional communication with the installation EE is established over the line L-L. The problem solved here consists in that the receiving station EE'can receive, in the indicated way, communications coming from the exchange line (A, B)--.normal use-and also from another, for instance, an internal line (L, L)special use. In Fig. 5, SE designates two batteries B and B1, a transformer AU and a key Ta, so that the emitted voice currents are transmitted to the line LL when the microphone M is controlled and simultaneously the key Ta is closed. Between the two wires of line L-L is arranged the winding S of a relay whose switch s is open in rest position. If the Key To is closed in the emitting direction SE, then a circuit: battery B1key Tasecondary winding of the transformer AUline L--relay winding S and back to the second wire of the line L to battery B1, is closed. Thereby the winding S becomes energized and the contact s, which is associated to the relay in question, is closed and short-circuits thereby the terminals 3, 4 which correspond to the terminals 3, 4 of Fig. 1. The effect obtained thereby has been described in connection with Fig. 1. With this artion and to connect it to the line L-L. This,

however, is not absolutely necessary. The terminals a, b and ER are adjusted in like manner as in the preceding examples.

The normal operating conditions require a permanent excitation-of the relay E, but only for a temporary operation of relay U (for changing the speaking direction). In the case of special use the conditions are in so far reversed, as relay U permanently carries current and relay E is constantly in rest position. In other words, both in normal operation and in special operation, the same relays are brought alternatively into action.

Accordingly, it is clear that for this alternative operation of the relays E and U a purely mechanical snap action can be used in such a way that this latter, at the moment of the operation of relay E, releases relay U.

If, in normal operation, EW is used by the subscriber as transmitter (e. g., for dictation), the readiness to receive calls is maintained provided that the contact e1-u3 can be bridgedover by a manual switch.

I claim:

1. A remote control automatic telephone subscribers station comprising a transducer, an amplifier having input and output connections from the amplifier to the transducer and to terminals for connecting the station with an exchange line, connections from the amplifier to another line differing from the exchange line, a first relay having operating contacts for reversing the input and output connections of the amplifier to control the speaking direction, a full wave rectifier bridge arrangement, connections includin a condenser for connecting the rectifier bridge with the exchange line including a condenser in parallel with said first relay, a second relay connected across the rectifier bridge and responsive to current supplied by the exchange line through said condenser, said second relay having operating contacts for switching the amplifier from the connections with said other line to the connections with the exchange line.

2. A remote control automatic telephone installation comprising an amplifier, an exchange line, means for connecting the amplifier to the exchange line, two contacts controlling the speaking direction, a relay having a high ohmic winding, a first terminal providing connections with another line different from the exchange line, leads from said terminal to the amplifier,

a condenser bridging the high ohmic winding, a second terminal connected to the high ohmic winding, a third terminal connected to the exchange line, a rectifier bridge arrangement comprising a full wave rectifier, a second relay having 'a winding which is connected across said rectifier, operating contacts associated to said second relay, and comprising a contact operable to disconnect the high-ohmic winding, and a second contact operable to disconnect the first terminal from the leads to the amplifier.

3. A remote control automatic telephone subscribers station, comprising a receiver and transmitter assembly, connections from said assembly to an exchange circuit and to another circuit difierent from said exchange circuit, a full wave rectifier bridge, means including a first relay windin for connecting the rectifier bridge with the exchange line, a second relay winding connected across the rectifier bridge, the resistance of said first relay winding being so high that current supplied therethrough is insufficient to operate the second relay, operating contacts associated with the first relay con-' trolling the speaking direction, operating contacts associated with the second relay for conmeeting the receiver and transmitter assembly alternatively with the exchange line on said other line, a calling dial having short-circuiting contacts connected with the exchange line and impulse contacts, and connections including said impulse contacts and a condenser in parallel with said first relay winding for connecting said rectifier bridge with the exchange line, thereby by-passing said first relay winding.

4. A circuit according to claim 3 in which operating contacts operable by both the first and the second relays are provided for connectin the receiver and transmitter assembly with a power source.

OTTO TSCHUMI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,486,868 Egerton Mar. 18, 1924 1,647,606 Coggeshall Nov. 1, 1927 2,036,023 Curl Mar. 31, 1936 2,102,903 Leveque Dec. 21, 1937 2,146,362 Thomsen Feb. 7, 1939 2,162,370 Campbell June 13, 1939 2,192,540 Creti Mar. 5, 1940 2,224,698 Roseby Dec. 10, 1940 

